The hole in the bottom of the mold is to string the wick through as you are making the candle. You will need to secure the wick at the top and bottom of the mold.

How do I wick a pillar candle?

All of our pillar molds have a hole in the bottom to accommodate wicking the candle while it is being poured. You string the wick through the bottom of the mold, secure it at the top and bottom so it can't move, and then you are ready to pour the wax. Some molds have an auto wick pin available that fit them which is a convenient alternative to wicking them while you pour.